Pesticidal compositions and methods containing phosphorous-containing esters of 2-thiomethyl mercapto pyrimidines



United States Patent Oflice 3,384,540 Patented May 21, 1968 3,384,540PESTICIDAL COMPOSITIONS AND METHODS CONTAINING PHOSPHOROUS-CONTAININGESTERS OF Z-THIOMETHYL MERCAPTO PY- RIMIDINES Arthur C. Thomson, SanAntonio, Tex., and Karoly Szabo, Orinda, Mervin E. Brokke, Richmond, andJulius J. Menn, San Jose, Calif., assignors to Stauiter ChemicalCompany, New York, N.Y., a corporation of Delaware No Drawing. Originalapplication July 14, 1965, Ser. No. 473,277, now Patent No. 3,313,814,dated Apr. 11, 1967. Divided and this application Jan. 30, 1967, Ser.No. 641,068

Claims. (Cl. 167-33) This is a division of application Ser. No. 473,277,filed July 14, 1965, now US. Patent No. 3,313,814.

This invention relates to certain compounds as composi tion of matterand the use of such compounds as insecticides and acaricides.Specifically, the invention relates to compounds of the formula ROXwherein R is a lower alkyl, R, is a lower alkyl or lower alkoxy, X issulfur or oxygen and R and R are selected from hydrogen or lower alkylgroups. By lower alkyl or lower alkoxy is meant such radicals containingfrom one to four carbon atoms.

The compounds of the present invention can be conveniently prepared inthe manner of the following nonlimiting examples. Compound numbers havebeen assigned to each compound corresponding to the example in which itis described and the numbers are used throughout the balance of theapplication.

Example 1.S-(4,6-dimethylpyrimidyl-2-thiomethyl)0,0-diethyl-phosphorothioate Sodium metal (1.42, 0.066 M) was dissolvedin 50 ml. of absolute ethanol and then there was added Z-mercapto-4,6-dimethylpyrimidine with adequate stirring. On gentle heating andagitation the pyrimidine formed the sodium salt and went into solution.This was followed by the addition of0,0-diethyl-S-(chloromethyl)-phosphorothioate (14.4 g.). The reactionmixture was refluxed for one hour. The mixture was poured into 150 ml.of water and extracted three times with benzene. The benzene layer wasdried with anhydrous sodium sulfate and filtered. The benzene wasevaporated under reduced pressure. There was obtained a yield of 90% ofthe title compound, a yellow, slightly viscous oily product, n =l.5273.

Example 2.S-(4,6-dimethylpyrimidyl-2-thiomethyl)O-ethyl-ethyl-phosphonodithioate By a procedure analogous to Example 1,the title compound was prepared. After refluxing the reaction mixturefor two hours the crude product was isolated in a similar manner in ayield of 85%. Upon recrystallization the purified product, a yellowsolid, M.P. 4848.5 C., was obtained.

Example 3.S- (4,6-dimethylpyrimidyl-2-thiomethyl)0,0-diethylphosphorodithioate To a solution of sodium hydroxide (8.0 g.,0.2 mole) and 2-mercapto-4,6-dimethylpyrimidine hydrochloride (16.4 g.,0.1 mole) in 200 ml. of ethanol was added with adequate stirring 23.7 g.(0.1 mole) of S-chloromethyl- 0,0-diethylphosphorodithioate. Theresulting mixture was Example 4.S- (pyrimidyl-2-thiomethyl) 0,0-diethylphosphorodithioate This compound was prepared in a manneranalogous to the procedure of Example 3. From 7.4 g. ofZ-mercaptopyrimidine hydrochloride and 11.7 g. of S-chloromethyl-0,0-diethylphosphorodithioate there was obtained 10.0 g. of the titlecompound, a yellow oil, 11 =1.5392.

The compounds have been tested as insecticides and as acaricidesaccording to the following methods.

Acaricidal evaluation test.The two-spotted mite, Tetranychus zelarius(Linn) was employed in tests for acaricides. Young pinto bean plantswere infested with several hundred mites. Dispersions of test compoundsare prepared by dissolving half a gram of he toxic material in tenmilliliters acetone. This solution was then diluted with watercontaining 0.015% Vatsol (a sulfonate-type wetting agent) and 0.005%Methocel (methyl cellulose) as emulsifiers, the amount of water beingsuflicient to give concentrations of active ingredient ranging from0.25% to 0.005%. The test suspensions were then sprayed on the infestedpinto bean plants. After seven and fourteen days, the plants wereexamined both for postembryonic forms of the mite as well as eggs. Thepercentage of kill was determined by comparison with control plantswhich had not been sprayed and the LD-50 value calculated usingwell-known procedures. LD-50 values are reported under the column 2 SMin the table and 2 SME indicates the embryonic forms.

Insecticidal evaluation tests-Three insect species were subjected toevaluation tests for insecticides:

(1) American cockroach (R0ach)--Periplanela americana (Linn).

(2) Large milkweed :bug (MWB)Onc0peltus fasciaius (Dallas).

(3) Housefiy (HF)-Musca dOmestica (Linn).

The procedure for the insects was similar to the miticidal testingprocedure. Test insects were caged in cardboard mailing tubes 3 /s" indiameter and 2 /8 tall. The cages were supplied with cellophane bottomsand screened tops. Ten to twenty-five insects were used per cage. Foodand water were supplied in each cage. The caged insects were sprayedwith the active compound at various concentrations. After twenty-fourand seventy-two hours, counts were made to determine living and deadinsects.

Housefly evaluation tests differ in this respect: The toxicant wasdissolved in a volatile solvent, preferably acetone, the active compoundwas pipetted into a petri dish bottom, allowed to air dry and placed ina cardboard mailing tube. Twenty-five female flies were caged in thetube. The flies were continuously exposed to the known residue of theactive compound in the cage. After twenty-four and seventy-two hourscounts were made to determine living and dead insects. The LD-50 valueswere calculated using well-known procedures. The folllowing LD50 valueswere obtained:

Compound HF, pg. Roach, MWB, 2 SM, 2 SM-E,

Number percent percent percent percent 1 Percent.

Upon evaluation of the root absorption of pinto bean J plants and upwardtranslocation of the compound, activity was found for compound number 1at 3 ppm.

From these data it can be seen that these compounds are valuable asinsecticides. In practice the compounds are usually formulated with aninert adjuvant, utilizing methods well-known to those skilled in theart, thereby making them suitable for application. They may be used inthe form of emulsions, nonaqueous solutions, wettable powders, vapors,dusts, dips and the like, as may be best fitted to the particularutility. The concentration of a compound of the present invention,constituting an effective amount, and the best mode of administration toa pest or its habitat may be easily determined by those skilled in theart of insect control. The disclosure is not meant to limit the actionof the compounds to one particular insect species or the mode of effectthereon.

Various changes and modifications may be made without departing from thespirit and scope of the invention described herein as will be apparentto those skilled in the art to which it pertains. It is accordinglyintended that the present invention shall only be limited by the scopeof the appended claims.

We claim:

1. The method of killing pests selected from insects and acaridscomprising applying an effective amount to a pest habitat of a compoundof the formula wherein R is lower alkyl, R is selected from the groupconsisting of lower alkyl and lower alkoXy, R and R are selected fromthe group consisting of hydrogen and lower alkyl, and X is selected fromthe group consisting of sulfur and oxygen.

2. A method of killing pests selected from insects and acaridscomprising applying an elfective amount to a pest habitat of thecompound S-(4,6-dimethylpyrimidyl-Z-thiomethyl)0,0-diethylphosphorothioate.

3. A method of killing pests selected from insects and acaridscomprising applying an effective amount to a pest habitat of thecompound S-(4,6-dimethylpyrimidyl-2-thiomethyl)O-ethyl-ethylphosphonodithioate.

4. A method of killing pests selected from insects and acaridscomprising applying an effective amount to a pest habitat of thecompound S-(4,6-dimethylpyrimidyl-Z-thiomethyl)0,0-diethylphosphorodithioate.

5. Amethod of killing pests selected from insects and acarids comprisingapplying an effective amount to a pest habitat of the compoundS-(pyrimidyl-Z-thiomethyl) 0,0-diethylphosphorodithioate.

6. An insecticidal composition comprising an inert pesticidal adjuvantand an effective amount of a compound having the formula ROX wherein Ris lower alkyl, R is selected from the group Consisting of lower alkyland lower alkoxy, R and R are selected from the group consisting ofhydrogen and lower alkyl, and X is selected from the group consisting ofsulfur and oxygen.

7. An insecticidal composition comprising an inert pesticidal adjuvantand an effective amount of the compound S-(4,6-dimethylpyrimidyl2-thiomethyl)0,0-diethylphosphorothioate.

8. An insecticidal composition comprising an inert pesticidal adjuvantand an effective amount of the compound S-(4,6-dimethylpyrimidyl2-thiomethy1)O,-ethylethylphosphonodithioate.

9. An insecticidal composition comprising an inert pesticidal adjuvantand an effective amount of the compound S-(4,6-dimethylpyrimidyl2-thiomethyl)0,0-di ethylphosphorodithioate.

10. An insecticidal composition comprising an inert pesticidal adjuvantand an effective amount of the compound S-(pyrimidyl 2thiomethyl)0,0-diethylphosphorodithioate.

References Cited UNITED STATES PATENTS 3,216,894 11/1965 Lorenz et a1.16722 3,244,586 4/1966 Rigterink 16733 MJBERT T. MEYERS, PrimaryExaminer. D. R. MAHANAND, Assistant Examiner.

6. AN INSECTICIDAL COMPOSITION COMPRISING AN INTERT PESTICIDAL ADJUVANT AND AN EFFECTIVE AMOUNT OF A COMPOUND HAVING THE FORMULA 